Not necessarily - a 10 spoke alloy rim will weigh less than the typical 5 spoke, because there is less aluminum there. Also, a rim with more open space wighs less than one with more - to the point my
16 inch torque thrusts weigh less than my 14 inch deerfoots.Usually aluminum -
Depends on the tire. With an LT tire, likely. With a "performance" passenger car tire, likely not
With one inch, likely no net loss - with 3 or 4, almost definitely in city driving.
You need to know that vehicles were often available with several different optional gear ratios. If it had a hign numeric rear end, like a 4.11 , you could gain milage with bigger tires - get the same mileage as sat 3.55 gears - or mabee 3.23. Buying 3.23 gears and then putting big tires on it generally would hurt mileage
On my Ranger, with 3.55 gears from rhe factory and they come as high as a 3.08 and as low as a 4.56. The bigger wheel is still not as high (effectively) as a 3.08 with the small wheels (would require a 15% oversize) I upsized 9% - so 3.25 woth the snows - a little less on the summer tires - 3.31 equivalent
With my scanguage calibrated to my GPS, over a 2 or 3 tank run I can be accurate to tenths
I used to have a gas milage tester that could be accurate to way less than a tenth - fuel consumption measured to within less than a cc.
With the fuel mileage rig I had (for carbureted vehicles) you could see the differnce made by changing tire pressure by a few PSI if the wind didn.t change. You could see the difference from winding down a window.
Nothing of value there.
LRR tires can also significantly reduce tire life. As long as the manufacturer can boost the CAFE numbers with an OEM LRR tire they are not concerned with the tire life. Replacement LRR tires tend to be more expensive than other options. Given the current gasoline prices I'm willing to give up a couple of mpg for better life and handling characteristics.
The outlaw karts are karts -- most of which have side mounted 600cc Honda two-strokes. As far as weight to horsepower they are right up there. You can get into it for under $10K too. I'd be seriously interested but I don't think they have a geriatrics class :)
The local track is a 1/6 mile dirt oval and they're turning laps under
10 seconds. It's fast even if it doesn't have the earth shaking roar the dirt track races of my youth did. I took my fiance -- once. She just about had a panic attack from the noise.
I am not at all disagreeing with you that different rims weigh different amounts where size isn't the only determinant of the weight.
I never disagreed. I'm just trying to control the variables in this thought experiment because I was trying to figure out what the benefit, alone, was of larger-diameter fitments.
Thanks. I didn't look up the density of the rubber versus the metal, mainly because the volume matters greatly and I would have no weigh of knowing that for this thought experiment.
I have to agree with you that the two reliable articles that referenced four inches of change all showed (and expected) huge losses in performance.
None of the articles seemed surprised at the losses, although the consumer reports article discussed that the measurements were such that they were within their measurement margin of error.
Take everything I say with a grain of salt because I'd have to dig up the references of where I got this idea that even the EPA can't get better than
4% (as I recall), and they don't measure volume (since that's inaccurate). They measure weight. And they used, as I recall, plastic bags filled with a known *weight* of fuel.In addition, they ran on test course, and they repeated the tests. And even then, they couldn't get better than 4% as I recall.
Unless I dig up the reference, that's all hearsay, but, as I recall, nobody is going to get accuracies and repeatabilities anywhere near decimal places at home if they're not repeating the tests under extremely well controlled circumstances and weighing the fuel consumed.
I use a Scangauge II plugged into the OBDII port. It's sort of accurate :)
I didn't change the wheel size but the OEM tires on my F150 looked pretty stupid. After they wore out I've always went for meatier tires on the same rims. The downside is the truck sits higher and working on the engine isn't quite as convenient.
I ran bias plies until they got to be very hard to find. Rough, noisy, and with sidewalls you could bounce volcanic rock off of all day. Radials have gotten better but they used to have very tender sidewalls.
Nothing changes. Remember the chopped and channeled bathtub Mercs that high centered on a cigarette butt?
Then there are the hoppers:
Who uses the classic odometer method? This is the age of computers.
Mad Roger lives in the past. What I find cute with the scangauge set for instantaneous reading is when you get off the throttle, the injectors shut off, and the reading goes to 99.999 mpg.
Don't bother. There was more bullshit in that thread than in a feedlot.
Thanks. By now you can tell that I care about two things:
My original opinion was that there was a performance benefit to larger-diameter fitments, but my new opinion is based on the facts unearthed in this thread, which is that you'd be hard pressed to gain the one known performance advantage, which is to put the engine into a sweeter spot on the torque curve.
However, even if you did that, there are many other factors, the next-biggest of which is the contact patch, but there are others such as the weight change, materials change, suspension change, etc.
Hence, larger fitments have, essentially, no performance advantage and most likely have a negative effect on performance overall in most cases.
If anyone has data that contradicts that opinion, I'm all ears.
I'm still looking for where I got that 4% accuracy figure for mpg calculations.
This article describes the two-part problem correctly but the article doesn't put a percentage on the results calculated at home. How accurate are gas mileage monitors?
Basically, everyone who gives you a MPG claim is wrong (IMHO) because they actually *believe* their accuracy and repeatability to figures which are, in reality, a figement of their imagination.
Sure, they can *see* the decimal places, but it's my current statement that I need to prove that anyone quoting numbers within + or - 1 mpg is probably fooled by lack of knowledge about what they're actually doing.
The two areas of huge inaccuracy are: a. The test conditions b. The test equipment
I'll check out these references which are in the back of the article. Allen, Mike. "3 Gadgets That Really Work." Popular Mechanics. DIY Auto. December
2008.http://www.popularmechanics.com/automotive/how_to/4294223.html?page=2 Allen, Mike. "How to Monitor Your Fuel Economy in Real Time on the Road." Popular Mechanics. June 9, 2008.http://www.popularmechanics.com/automotive/how_to/4267957.html
From what I read long ago, we're not going to get anywhere near decimal place accuracy at home, but I need to check this out to be sure of my figures before I can argue it effectively with you.
Here's a seemingly expensive "fuel economy meter" which shows the complexity of calibration, heated probes, high-speed sampling, auto zero, etc. whose specs show a "resolution" of "? 2% reading" and a "repatability" of "?2 % of reading" with a "span drift" of "?2 % of reading"
Remember I said 4% accuracy, so let's see if my statement holds water over the next few days. If that is correct, then anyone quoting accuracy with a decimal place in it is ridiculously misled.
Doing a quick search, Car & Driver says the EPA gets to 1% with what appears to be a 350 million dollars investment in tools.
"Measuring fuel economy during the tests is likewise hugely complex, which is why the automakers and the EPA both follow precisely the same protocol. For openers, the chemical composition of fuel varies slightly, so simply retrieving it from a local gas station won??t produce repeatable results. The EPA has a specialized company manufacture small batches of consistent fuel, which is 93 octane ... Before being used, the gas is analyzed to measure its properties, and fuel economy is then calculated based on the measured carbon content of the various tailpipe emissions?Xunburned hydrocarbons, carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), and oxides of nitrogen (NOx)?Xthat are collected in bags made of a special Kynar plastic. A $350,000 gas-analyzing machine then makes minute measurements. The one-percent accuracy of this machine from Japanese company Horiba is amazing considering the minuscule amounts of some of the exhaust constituents?Xsome in quantities as low as a half-dozen parts per million.
So what's 1% to a typical consumer?
Reading the whole article, I can't tell if that 1% is 1% of 20mpg or 1% of
18 gallons.If it's 1% of, say, 20 mpg, then that could mean it's +/- 0.2 mpg (or 19.8 mpg to 20.2 mpg). If it's 1% of, say, 20 gallons, then that could mean it's +/- 0.2 gallons (or 19.8 gallons to 20.2 gallons).
Fuel-Economy Face-Off: Driving With Windows Open or With A/C Running?
Q. Does a car use more gasoline when you drive with the windows rolled down or the air conditioning turned on?
A. ?We found that on an 85-degree day, running the A/C can reduce fuel economy by 1 to 4 mpg, depending on the car....[while] the effect of opening the windows at 65 mph did not measurably reduce fuel economy,?
Back when I had the use of the unit, AC was not as efficient as it is today, but at low speeds it was more efficient to open the windows, although a lot less effective here where relative humidity is quite high. At highway speeds the extra drag from open windows and all the bufetting inside the car made the AC more efficient. I strongly suspect the same is still true today with more efficient AC - perhaps the "transition speed" is lower today.
I know running with the windows open at 60 MPH across Kansas and Oklahoma back in 1976 did NOTHING to make the cab of my 1957 Fargo more comfortable, so whatever the mileage hit for AC, IT WAS ON!!!!
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.